Analysis of the effect of microsphere-lens material spectral absorption on the overall FTIR spectral response sensitivity of MWIR (3μm-5μm) microsphere-lens-enhanced SLS photo detectors

Relatively recently, it has been shown that the addition of microsphere lenses to mid wave infrared (MWIR) strained layer super lattice single (SLS) photo detectors, has exhibited an increase in detector sensitivity. In this work we present a signal processing and data analysis method to characterize, estimate and analyze the effect of microsphere material absorptions on the overall microsphere-lens-enhanced MWIR detector sensitivity. Our findings show that the spectral absorptions of the detector without-microsphere-lens-enhancement are removed and/or relatively significantly reduced by the microsphere-lens, as a function of the wavelengths. Our findings also show that, at this scale, the resulting integrated microsphere-lens-enhanced detector overall FTIR absorptions depend dominantly on the microsphere selected material and generally not on the detector material.